[unreadable] [unreadable] The Biostatistics Center of George Washington University will participate as the Data Coordinating Center (DCC) for the "Prospective Investigation Pulmonary Embolism Diagnosis Pulmonary III (PIOPED III)", which will assess the diagnostic validity of magnetic resonance angiography (MRA). This proposal is a companion application to that submitted by Paul Stein, MD, study chair, and 7 clinical investigators. The DCC Principal Investigator, Sarah Fowler, PhD, specializes in the design, conduct and coordination of multi-center studies, and has extensive experience in studies involving imaging. She will work closely with the collaborative group to assure the timely conduct of the study, coordinate and track the image reading, oversee data quality assurance, maintain a central database of study data, and collaborate with the other investigators on the statistical analysis and publication of study results. [unreadable] [unreadable] Working committees of the investigators will conduct reading and interpretation of images so that no investigator reviews images from his own center, and two independent readings (with adjudication if necessary) will be done for each image. The DCC will be responsible for designing and implementing the study's image transfer system. The DCC will provide a web-based image tracking system through which the DCC and image readers will track the exchange of images from the originating clinical center, through the DCC, to the blinded "central" readers, and back to the DCC for archiving. Central readers will be blind to the patient's clinical assessment, and the results of all imaging studies except the one for their reading. [unreadable] [unreadable] The study will evaluate MRA in the broadest possible group of patients with suspected PE. Reading agreement and adjudication criteria and quality control procedures have been established. [unreadable] [unreadable]